<?php
class commonMysql{
    
    public $db="big";

    public $mysqlIp="localhost";

    public $userDb="root";

    public $userPwd="root";

    protected $conn=null;

    public function __construct()
    {
        $conn=$this->conn=mysqli_connect($this->mysqlIp,$this->userDb,$this->userPwd);

        mysqli_select_db($conn,$this->db);
        mysqli_query($conn,"set names utf8");
    }
}